Sheathing

[Akiko Kobayashi]

I have a query about the sheathing - is it adequate for only one layer of sheathing (external) to be used for racking/bracing. I'm assuming it's needed to be well fixed for the whole structure to act as a stressed box, so what screw spacings are recommended? And for either OSB3 or spruce ply, what specification's been used in the most recent prototype (Spax?)

Thanks

Akiko